UC Riverside UC Riverside Electronic Theses and Dissertations Title Phase Resolved Optical Coherence Tomography for Label-Free Detection of Neural Activity Permalink https://escholarship.org/uc/item/43g020nw Author Tong, Minh Publication Date 2018 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA RIVERSIDE Phase Resolved Optical Coherence Tomography for Label-Free Detection of Neural Activity A Dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Neuroscience by Minh Quang Tong December 2018 Dissertation Committee: Dr. B. Hyle Park, Co-Chairperson Dr. Michael E Adams, Co-Chairperson Dr. Hongdian Yang Copyright by Minh Quang Tong 2018 The Dissertation of Minh Quang Tong is approved: Committee Co-Chairperson Committee Co-Chairperson University of California, Riverside ACKNOWLEDGEMENTS Thank you, Dr. B. Hyle Park, for your patience and guidance during that last four years. Your patience is of a saint. You were able to handle all my mistakes, even those that resulted in the failure of an entire optical system. Your guidance is of a light house. You were there to provided valuable suggestions but also allowed me to explore new ideas. All this work would not be possible without your support. I wish your family the best! I would also like to thank my dissertation committee members, Dr. Michael Adams and Dr. Hongdian Yang, for their time to review my project through the years and providing valuable feedback. Dr. Michael Adams has been knowledgeable and supportive through my entire graduate school life, without him I would be lost, thank you so much. In addition, I would like to thank my oral qualifying committee members, Dr. Devin K. Binder and Dr. Xiaoping Hu for reviewing my proposal and guiding me to achieve it. I would have become insane and lonely if it were not for the support of my lab mates. I would like to thank Dr. Rezuanul Haque for being a mentor when I first rotated in the lab during the summer. Thank you, Christian Oh, for being a great friend and mentor while I was still learning how to align the 800 system. Thank you, Dr. Koji Hirota for your continued support even after your graduation but most importantly for being a great friend. Thank you, Dr. Monirul Hasan for not only being a great friend but struggling with me as we aligned the 800 system for tomorrow’s experiment or going out for curry. Thank you, Jorge Sanchez for being a friend and keeping me company while I was aligning the OCT system or programming. I owe you some Taco Bell. Thank you, Jason Qiu for your iv friendship and for putting up with my “Minh” jokes. Thank you, Dr. Michael C. Oliveira, Dr. Carissa Rodriguez, Danielle Ornelas, Christopher Lee Hughes, Junze Liu, Jasmine Shah, and Patrick Gregory for your support on all the different projects. All of you are amazing people. I would also like to thank the neuroscience and bioengineering communities. I would like to acknowledge the funding sources that contributed to the work, which includes the NIH R00 EB007241, NIH R01 NS081243, CAL-BRAIN 349329, NIH R21 EY026441, NIH U01 EY025501, and the CNAS deportment for allowing me to be a teaching assistance. Lastly, I would like to thank my family for supporting me throughout my Ph.D. journey and beyond. Thank you, Ba and Mẹ for your support. Thank you, Linh, Tam, and Brian for being amazing siblings. Minh Tong Riverside, California v To my family For their lifelong dedication, love, care and support vi ABSTRACT OF THE DISSERTATION Phase Resolved Optical Coherence Tomography for Label-Free Detection of Neural Activity by Minh Quang Tong Doctor of Philosophy, Graduate Program in Neuroscience University of California, Riverside, December 2018 Dr. B. Hyle Park, Co-Chairperson Dr. Michael E Adams, Co-Chairperson Current methods for detection of nervous system activity have been limited to electrophysiology, which requires the electrode to contact the nervous system or optical- based techniques that require incorporation of reporter agents. Both methods are golden standards but have limitations. Optical coherence tomography (OCT) is an imaging technique based on light that measures intrinsic structural changes associated with an action potential. A benefit of using OCT is that it does not require any exogenous agents and is minimally invasive. Phase-resolved OCT detects 1-30 nm swelling of an axon during neural activity. In my studies described here, phase-resolved OCT was used to detect the swelling Drosophila neurons when presented with ecdysis triggering hormone as well as a 1-3 nm swelling of a cockroach axon caused by action. However, since phase imaging is limited to one point, the dissertation ends with development of the line field swept source OCT system that can provide images of a b-line or cross-sectional image without using a scanning device. vii Table of Contents Introduction…….…………………………………………………………………………1 Chapter 1 : Introduction of Optical Coherence Tomography ............................................. 4 1.1. Optical coherence tomography (OCT) .................................................................................. 4 1.2. Principle of OCT ................................................................................................................... 4 1.2.1. Fourier Domain OCT ..................................................................................................... 5 1.2.2. Phase-resolved OCT .................................................................................................... 12 1.3. Applications of OCT ........................................................................................................... 15 1.4. OCT in neuroscience ........................................................................................................... 16 1.5. Conclusion .......................................................................................................................... 17 Chapter 2 : Combining optical coherence tomography with electrophysiology and fluorescence ................................................................................................ 18 2.1. Introduction ......................................................................................................................... 18 2.2. System development ........................................................................................................... 19 2.2.1. Spectral domain optical coherence tomography (SD OCT) ........................................ 19 2.2.2. Fluorescence microscopy (FM) ................................................................................... 21 2.3. System characterization ...................................................................................................... 22 2.3.1. Characterization of OCT systems ................................................................................ 22 2.3.2. Fluorescence characterization, data acquisition, and processing ................................. 26 2.4. Conclusion .......................................................................................................................... 28 Chapter 3 : Non-contact Detection of Neural Activity During Fictive Ecdysis Behavior using Phase-resolved Spectral Domain Optical Coherence Tomography .. 29 3.1. Introduction ......................................................................................................................... 29 3.2. Materials and methods ........................................................................................................ 31 3.2.1. Animals ........................................................................................................................ 31 3.2.2. CNS preparation ........................................................................................................... 31 3.2.3. Imaging system ............................................................................................................ 32 3.3. Results and Discussions ...................................................................................................... 32 3.3.1. OCT data acquisition and processing ........................................................................... 32 3.3.2. Fluorescence data acquisition and processing.............................................................. 35 3.3.3. Correlation between optical changes and calcium flux ................................................ 37 3.4. Conclusion .......................................................................................................................... 40 viii Chapter 4 : Non-contact Detection of Neural Activities in Functionally Stimulated Cockroach Nervous Systems using Phase-resolved Spectral Domain Optical Coherence Tomography .............................................................................. 41 4.1. Introduction ......................................................................................................................... 41 4.2. Materials and methods ........................................................................................................ 42 4.2.1. Animals ........................................................................................................................ 42 4.2.2. Dissection of cockroach ............................................................................................... 42 4.2.3. System description ......................................................................................................